Laparoscopic hifu probe

ABSTRACT

A high-intensity focused ultrasound ablation of tissue using minimally invasive medical procedures is provided.

This application is a divisional of U.S. patent application Ser. No.11/445,004, filed Jun. 1, 2006, titled “LAPAROSCOPIC HIFU PROBE”, DocketFOC-P004-01 which claims the benefit of U.S. Provisional ApplicationSer. No. 60/686,499, filed on Jun. 1, 2005, the disclosures of which areexpressly incorporated by reference herein.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to instruments to conduct minimallyinvasive medical procedures with the aid of laparoscopic techniques, andto such procedures themselves. More particularly, the present inventionrelates to high-intensity focused ultrasound ablation of tissue usingminimally invasive medical procedures.

Several minimally invasive and non-invasive techniques for the treatmentof living tissues and organs with ultrasound, including high-intensity,focused ultrasound, sometimes referred to hereinafter as HIFU, areknown. There are, for example, the techniques and apparatus described inU.S. Pat. Nos. 4,084,582; 4,207,901; 4,223,560; 4,227,417; 4,248,090;4,257,271; 4,317,370; 4,325,381; 4,586,512; 4,620,546; 4,658,828;4,664,121; 4,858,613; 4,951,653; 4,955,365; 5,036,855; 5,054,470;5,080,102; 5,117,832; 5,149,319; 5,215,680; 5,219,401; 5,247,935;5,295,484; 5,316,000; 5,391,197; 5,409,006; 5,443,069; 5,470,350;5,492,126; 5,573,497; 5,601,526; 5,620,479; 5,630,837; 5,643,179;5,676,692; 5,840,031. The disclosures of these references are herebyincorporated herein by reference.

HIFU Systems for the treatment of diseased tissue are known. Anexemplary HIFU system is the Sonablate® 500 HIFU system available fromFocus Surgery, Inc. located at 3940 Pendleton Way, Indianapolis, Ind.46226. The Sonablate® 500 HIFU system uses a dual-element, confocalultrasound transducer which is moved by mechanical methods, such asmotors, under the control of a controller. Typically one element of thetransducer is used for imaging and the other element of the transduceris used for providing HIFU Therapy.

Further details of suitable HIFU systems may be found in U.S. Pat. No.5,762,066; U.S. Abandoned patent application Ser. No. 07/840,502 filedFeb. 21, 1992, Australian Patent No. 5,732,801; Canadian Patent No.1,332,441; Canadian Patent No. 2,250,081; and U.S. Pat. No. 6,685,640,the disclosures of which are expressly incorporated by reference herein.

As used herein the term “HIFU Therapy” is defined as the provision ofhigh intensity focused ultrasound to a portion of tissue. It should beunderstood that the transducer may have multiple foci and that HIFUTherapy is not limited to a single focus transducer, a single transducertype, or a single ultrasound frequency. As used herein the term “HIFUTreatment” is defined as the collection of one or more HIFU Therapies. AHIFU Treatment may be all of the HIFU Therapies administered or to beadministered, or it may be a subset of the HIFU Therapies administeredor to be administered. As used herein the term “HIFU System” is definedas a system that is at least capable of providing a HIFU Therapy.

The laparoscopic probe of an illustrated embodiment of the presentinvention is targeted for minimally invasive laparoscopic tissuetreatments of the kidney and liver. The probe is light weight, easy touse, and adaptable to the current Sonablate® 500 HIFU system. Thelaparoscopic probe, with the Sonablate® 500 system, illustrativelyprovides laparoscopic ultrasound imaging, treatment planning, treatmentand monitoring in a single probe. The probe fits through a trocar(illustratively an 18 millimeter diameter trocar). A removable, sterile,and disposable probe tip includes a coupling bolus which covers the tipof the probe. The bolus is very thin and illustratively expands to abouttwo or three times its size when water is introduced. This provides awater medium surrounding the probe which is needed for ultrasonicimaging and treatment. Cooling the transducer that provides the imagingand treatment is achieved through a sterile, distilled, degassed passiverecirculating water system. The entire probe is ethylene oxide (EO)sterilizable, and the cooling system is gamma-sterilizable.

The laparoscopic probe of the present invention provides an alternativesolution to invasive surgery. As a result, recovery time is reduced andhospital visits are considerably shorter. In addition the ablationprovided by the laparoscopic probe permits the surgeon to target tissuewithout stopping the blood supply to the organ. For example, to performa partial nephrectomy in a conventional manner, the surgeonillustratively shuts off the supply of blood to the kidney and has alimited amount of time to excise the targeted tissue, seal the bloodvessels and restart the blood supply to the kidney. If the surgeon takestoo long, damage to the kidney and possible organ death may occur. Thusbeing able to treat large and small volumes of tissue while permittingblood flow to the organ is a significant contribution.

Additional features of the present invention will become apparent tothose skilled in the art upon consideration of the following detaileddescription of illustrative embodiments exemplifying the best mode ofcarrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description of the drawings particularly refers to theaccompanying figures in which:

FIG. 1 is a perspective view of a portion of the laparoscopic probe ofthe present invention including a controller, a drive mechanism, and amovable transducer;

FIG. 2 is a perspective view of a removable probe tip assembly of thepresent invention including an expandable bolus for acousticallycoupling the transducer to a targeted area and for cooling thetransducer during the procedure;

FIG. 3 is an exploded perspective view of the removable probe tipassembly of FIG. 2;

FIG. 4 is a side elevational view of the removable probe tip assembly ofFIGS. 2 and 3;

FIGS. 5A and 5B illustrate sterile kit packages for use in a fluidrecirculation system of the present invention;

FIG. 6 illustrates a fluid recirculation system of the present inventionwhich controls expansion of the bolus of the laparoscopic probe and alsoprovides cooling to the transducer;

FIG. 7 is a sample screen shot for planning a HIFU Treatment;

FIGS. 8A-8C illustrate a treatment path along which the transducer ismoved by the controller and drive mechanisms to treat a treatment zone;and

FIG. 9 is a screen shot illustrating a sample procedure in accordancewith an illustrated embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

U.S. application Ser. No. 10/380,031, owned by Focus Surgery, Inc.located in Indianapolis, Ind., discloses a HIFU laparoscopic probe andminimally invasive treatment procedure. The '031 application isexpressly incorporated by reference herein.

In an illustrated minimally invasive procedure as described in the '031application, in a HIFU-based procedure for treatment of a kidney, thepatient is first prepared. Next, three incisions are illustratively madeon the abdomen below the diaphragm through trocars. The trocars are leftin place, as is customary, to permit the sealing of the abdomen wheninstruments are passed through the seals of the trocars into the abdomenfor the conduct of the procedure.

A laparoscope for providing visual observation of the surgical field ispassed through one of the trocars. The laparoscope is conventionallycoupled to a video camera and a light source for illuminating thesurgical field and returning images to a surgical monitor. Thelaparoscope provides a pair of fiberoptic ports, one an output port forlight from source to the surgical field, and one an input port for thereturning image information to video camera. A second of the trocarsprovides, among other things, a passageway for the introduction into theabdomen of a relatively inert gas, such as, for example, carbon dioxide,from a source in order to permit the inflation of the abdomen below thediaphragm. This increases the space inside the abdomen for maneuveringsurgical instruments including the laparoscope, and provides a clearerview of the surgical field.

The third trocar provides access through the abdominal wall and into thesurgical field for a HIFU probe which is used to ablate the surgicalsite of a diseased kidney, for example, for the virtually bloodlessablation of (a) tumor(s) on the surface of, and/or within, the kidney.Should the surgical procedure call for it, additional trocars can, ofcourse, be provided for passing into the body additional HIFU probes 90to be used in conjunction with each other in an ablation procedure. If atumor is difficult to visualize, a catheter may be used to permit theintroduction into the surgical field of (an) ablation enhancing medium(media) and other media at (an) appropriate time(s) during theprocedure. The same, or a different, medium (media) may also beintroduced through the catheter to improve the accuracy of the targetingof the surgical site for ablation and provide feedback to the treatingphysician of the progress of the treatment. For example, lesions whichare not on the surface of the tissue being treated are not easilyvisible, or in many cases visible at all, in the laparoscopicallyinformed monitor.

In order to provide feedback to the treating physician of the progressof treatment of a site not visible on the monitor, the ultrasound probeincludes an ultrasound visualization capability. Additional mechanismsmay be provided for essentially real-time monitoring of the progress ofthe treatment. For example, it is known in the ultrasound visualizationand therapy arts that there are numerous mechanisms available to promotevisualization of the progress of ultrasound treatment within an organ ortissue.

The probe is illustratively integrated into, or mounted to bemanipulated by, a drive mechanism, and controlled, for example, by meansof a joystick, keypad, touch screen, or any other appropriate controlmechanism such as controller. Any of such mechanisms can incorporatefeedback control, not only of a visual nature, provided via alaparoscope, but also of the ultrasound imaging type via probe.

As shown in FIG. 1, the probe 90 includes a segmented, curvedrectangular elliptical transducer 100 of the general type described in,for example, WO 99/49788. The transducer 100 has a central segment 102which is used both for visualization and therapy and outer segment(s)104 which is (are) used for therapy, in accordance with knownprinciples. However, it will immediately be appreciated that othersingle element or multi-segment transducer configurations, such as onesproviding variable focal length, can be used to advantage in otherembodiments of the invention. Some of such variable focal lengthconfigurations, and driving and receiving systems for them, aredescribed in the prior art incorporated herein by reference.

The structure of the laparoscopic probe 90 is composed of two maincomponents, the main body or frame, and the probe tip assembly 111. Theframe illustratively provides a drive mechanism 92 for moving thetransducer 100 back and forth in the direction of double headed arrow106 in FIG. 1 (50 mm minimum movement), and also to rotate thetransducer 100 about its axis 107 as illustrated by arrow 108. It isunderstood that other suitable drive mechanism(s) 92 may be used to movethe transducer 100 (90° minimum rotation (+/−45°).

The probe tubing assembly 110 is primarily made from stainless steel.There are illustratively two bushings that guide the water tubing to thetransducer as well as provide support for access to the coupling of thetransducer shaft 109 and the hexagonal shaft. The transducer shaft 109is coupled to the hex shaft (mentioned above) and is able to rotate andtranslate for both imaging and continuous HIFU Treatment.

The probe tip illustratively includes two components: a main stainlesssteel tubing body 110 shown in FIG. 1 which illustratively has a 17 mmdiameter or less to fit into an 18 mm trocar, and a removable tipassembly 111 shown in FIGS. 2-4. The main tubing body 110 illustrativelyhas a threaded end 113 that connects with threads formed in distal end114 of the removable tip 111. The removable tip 111 also includes adistal end 116 having a rounded tip 148 coupled thereto. The internalthreading 115 (best shown in FIG. 3) has the threads removed on oppositesides of the tubing (see area 119) to permit the transducer to pass intothe tip. A coupling water bolus 118, a curved thin stainless steel shimmaterial 120, and two short pieces of very thin heat shrink tubing 122,124 complete the illustrated removable tip 111 components. The removabletip 111 is illustratively made from stainless steel but may be moldedfrom a resin such as Ultem® resin or other suitable material. The bolus118 is illustratively formed from a polyurethane membrane or condominserted over the end of probe tip 111. Bolus 118 is illustratively atubular membrane with a sealed end 141 best shown in FIG. 3. A shim 120is then located over the bolus membrane 118 on an opposite side of atreatment aperture 117. Shim 120 is coupled to the tip 111 only by twoheat shrinking tubes 122 and 124 best shown in FIGS. 3 and 4. Tubes 122and 124 have a thickness of about 4-5 thousandths of an inch.Illustratively the membrane is made from HT-9 material available fromApex Medical. The heat shrink tubing is illustratively made from ultrathin polyester tubing and is made by Advanced Polymers. The removabletip assembly 111 is designed to be disposable (USP—Class VI) andsterile. Sterilizing the removable tip can be achieved via ethyleneoxide (EO) sterilization or gamma sterilization.

The tubes 122 and 124 are very thin and facilitate insertion of theprobe tip 111 through the trocar 60. Tubes 122 and 124 minimize thethickness of the tip 111 which is desirable for laparoscopic procedures.Additional adhesives or other securing means are not required to securethe shim 120 to the bolus 118 or tip 111.

As discussed above, the removable tip 111 includes a housing 135 formedto include an opening or aperture 117. The transducer 100 is movablewithin the aperture as controlled by the drive mechanism 92 andcontroller 93 to provide the HIFU Therapy. Transducer 100 is configuredto emit ultrasound energy through the aperture 117 in the direction ofarrow 137 which is referred to as a treatment direction.

The housing 135, the tubes 122, 124 and the shim 120 work together tocause the bolus 118 to expand only in the treatment direction 137 inFIG. 4. The shim 120 forces the bolus 118 to expand in the direction ofthe opening 117 in the removable tip 111 as shown in FIG. 2. The heatshrink tubes 122, 124 hold the shim 120 in the desired position as wellas constraining the ends of the bolus membrane 118. The expansion of thewater bolus 118 acoustically couples the ultrasound to the patient. Italso changes the location of the transducer focus with respect to thetarget targeted area, thereby changing the position of the targetedtissue with respect to distance from the transducer 100.

As discussed above, the stainless steel shim 120 is an element used tocontrol expansion of the water bolus 118 during a treatment. Removingthe stainless steel shim 120 would result in a uniform expansion of thewater bolus 118 around the probe tip 111 in the presence of no externalobjects. With no shim 120 applying pressure to hold the probe againsttissue for treatment at a specific distance would result in the bolus118 reacting by shifting water behind the probe tip and away from thetissue. This may result in a poor and uncontrolled acoustic coupling ofthe transducer 100 to the tissue and the inability to accurately placethe HIFU Treatment zones in their desired locations.

The bolus membrane material 118 illustratively has a memorycharacteristic. This provides a substantially flat elevated position ofbolus 118 above aperture 117 for uniform contact and coupling with alarger tissue area. Once the probe 90 is positioned within a body, acontroller controls drive mechanisms to move the transducer 100 toprovide HIFU Therapy.

Providing a sterile, distilled, degassed water recirculation system forcooling and acoustic coupling during treatment is another illustratedaspect of the present invention. The water should be sterile due to therequired sterile surgical environment and degassed for the successfuloperation of the HIFU transducer.

The present invention contains components that work together both insideand outside the sterile fields during the procedure. For instance awater reservoir 200 is placed under a conventional chiller which islocated outside the sterile field as shown in FIG. 6. However, thedegassed water inside the reservoir 200 remains sterile because it onlypasses through a sterile environment. The inside of the tubing issterile thus the use of a non-sterile peristaltic pump 208 maintains thesterility of the water. After passing through the pump 208, the tubingenters the sterile field surrounding the patient. The tubing isconnected to the back of the probe and water is pumped through the waterbolus 118 and back out to the water reservoir 200.

The reservoir 200 and tubing are illustratively produced as a firststerile kit in an enclosed, sealed package 204 with the tubing primedwith sterile, degassed water as shown in FIG. 5A. A second sterile kitin an enclosed, sealed package 206 contains the components needed toprime the probe 111 and control the volume of water within the waterbolus 118. The second kit 206 illustratively includes a female luer lock207, a syringe 252, a stopcock 253, a filled 125 mL bottle 250 ofdistilled, degassed sterile water, sterile ultrasound coupling gel,o-rings and the removable probe tip 111 discussed earlier as illustratedin FIG. 5B. Since the probe tip 111 and everything that comes in contactwith it must be sterile, both of these kits are sealed in sterilepackaging 204, 206 (such as Tyvek material) and are gamma irradiated.

The water reservoir 200 acts as a heat sink in order to maintain thetemperature of the transducer at safe operating levels (belowapproximately 30° C.). In addition, the water reservoir 200 is made froma rigid material in order to maintain a constant volume which is neededfor control of the water bolus 118 height. The water bolus 118 providesa pressure release surface so the pressure within the water bolus 118 isclose to zero gauge pressure. A peristaltic pump 208 illustrativelycreates either a vacuum or a positive pressure within the waterreservoir 200 and the reservoir 200 must be able to withstand thispressure. The addition or subtraction of water to the water reservoir200 results in changes to the water bolus 118 volume. Glass wasillustratively chosen for the water reservoir 200 because of its rigidproperties as well as the ability to maintain the degassed nature of thewater compared to plastic (several months) over long periods of time(shelf life).

The water reservoir 200 is illustratively large enough, for example fourliters in size, to act as a heat exchanger and remove heat from thewater re-circulated to the probe. Therefore, a conventional activechiller does not need to be used in order to cool the water.Conventional chillers are typically not sterilized. Therefore, if thechiller was used, sterility of the water re-circulated to the pump wouldbe broken. The large thermal mass provided with the water withinreservoir 200 provides a suitable heat sink.

The preparation for a typical surgical procedure involves the followingsteps:

-   -   1) Placing all contents of the two kits 204, 206 within the        sterile field.    -   2) Attaching the probe tip 111 to the probe    -   3) Priming the probe tip using a syringe and the additional        bottle of degassed, distilled, sterile water.    -   4) Attaching the tubing to the main probe body 110.    -   5) Passing the water reservoir 200 out of the sterile field,        hanging it below the chiller (or other desired location), and        placing the pump compatible tubing 222 through the peristaltic        pump 208.    -   6) Filling the syringe 252 with degassed, distilled, sterile        water from bottle 250, attaching the stopcock 253 and passing        the syringe 250 out of the sterile field. This syringe 252 is        then attached to the third tube 240 coming out of the top cap        220 of the water reservoir 200 to control the bolus water        volume.    -   7) Turn on the pump 208.    -   8) Remove all air bubbles from the probe tip housing.    -   9) Inflate the water bolus 118 and shape the bolus 118 for the        treatment, see FIG. 2. The water bolus material 118 will        “remember” the shape it took when it was last inflated.    -   10) Coat the water bolus 118 and tip 111 with ultrasound        coupling gel.    -   11) Deflate the water bolus 118 for insertion into the trocar 60        using the syringe 252, now outside of the sterile field.    -   12) Position probe and adjust the water bolus 118 to obtain the        desired transducer/probe positioning/coupling.

Referring to FIGS. 5A and 6, the water reservoir 200 illustrativelyprovides a large volume of water, preferably about four liter(s) heldwithin the glass container or reservoir 200. The reservoir 200 is sealedwith a cap 220. A first tube section 222 is coupled to cap 220 by aconnector 224. Connector 224 is coupled to an internal tube 226 havingan open end located near a bottom of the reservoir 200. Illustratively,tube section 222 is special tubing made from C-Flex® by Masterflex®designed to fit within the pump 208. Tube 222 is coupled to another tubesection 225 by connectors 227. An end 228 of tube 225 is configured tocouple to a fitting on the probe tip 111. Tube section 230 includes anend 229 that couples to the other fitting of probe tip 111. Tube section230 extends from the probe tip 111 back to a second connector 232 on cap220. Tube section 230 is coupled to an internal tube 234 located withinreservoir 200 and provides return fluid to the reservoir 200 from thebolus 118. Illustratively, tube sections 226 and 234 extend more thanhalf way down into the fluid within the reservoir 200. The water isdegassed, distilled and sterile. If desired, the water could bedeionized. In the illustrated embodiment, tube 226 is located near thebottom of reservoir 200. The bottom of reservoir 200 likely contains thecoolest water and is spaced apart from any air in the reservoir 200 thatcollects at the top of reservoir 200 near cap 220. As discussed above,the last few feet of the end portions of tubes 225 and 230 remain insidethe sterile field (see FIG. 6) while the remaining components of thekits are passed outside the sterile field. A syringe 252 is configuredto be coupled to connector 236 which is in turn, coupled to cap 220 by aconnector 238 and a tube section 240. Normally open pinch clamps 223 and231 are coupled to tubes 222 and 230, respectively. If needed, pinchclamps 223 and 231 and be closed to stop the flow of water therethrough.For instance, if the surgeon needs to replace the probe tip 111, thesurgeon first turns the pump off, then pinch the clamps 223 and 231 canbe closed to seal the tubes 222 and 230, respectively.

As discussed above, before the tube sections 225 and 230 are coupled tothe probe tip 111, the probe tip is first primed using a syringe 252 andfluid from a container 250 located in kit 206. The bolus 118 is filledwith the sterile water and the syringe is also filled or loaded withsterile water and transferred outside the sterile field and connected toconnector 236 to control the expansion of bolus 118 from outside thesterile field.

The prediction on the size of the reservoir 200 required for adequatecooling is based on heat transfer from a probe [output level at maximum,TAP (total acoustic power)=39 W] an provides a conservative estimate ofheating for a volume of water starting at room temperature (25 C).

Question: How many cycles (15 minutes HIFU ON and 2 minutes HIFU OFF)can 3.2 L of water starting at room temperature (25 C) withstand beforereaching 30 C? Theoretical Prediction based on heat capacity of thewater: 2.5 cycles to raise the temperature to 30 C.

ΔT=Pt/(cρV)

Where the variables are defined as:

P=power (assume efficiency of transducer is 50% thus this is equal toTAP)

V=volume of the water reservoir

t=time

c=specific heat of water

ρ=density of water

ΔT=change in temperature

Experiment: 4 cycles were completed before raising the temperature ofthe water to 30 C (similar results were found for a second experiment).Thus a gallon (3.8 L) of water at or below room temperature shouldsuffice to cool the probe adequately for a procedure of reasonablelength.

Upon completion of the above steps the user plans and performs the HIFUtreatment using software running on the Sonablate® 500 system connectedto the laparoscopic probe 90. The physician uses the real time imagecapability of the laparoscopic probe to aid in the final placement ofthe probe. When the positioning is complete, an articulated arm holdingthe probe 90 is locked into place. The physician judges a real timeimage in both sector (rotating side to side transverse to the probeaxis) and linear (back and forth along probe axis) motion (“bi-plane”images). Depending on the positioning and physician preference, eitherthe linear or sector image may be chosen or the physician may alternatebetween the two. After physically moving the probe, fine tuning to theposition of the treatment region is achieved by moving the treatmentregion using software controls 301. This adjusts the position oftransducer 100 within the probe housing 135 resulting in fine tuning ofthe tissue treatment area. FIG. 7 displays an illustrated user interfacewith the treatment zones moved from the default center positions.

Once the treatment zone is positioned and resized by the physician tocover the desired tissue region (for example, a tumor), the HIFUTreatment is started and the probe begins to apply HIFU Therapy withinthe chosen region. The transducer trajectory is calculated by a seriesof algorithms that permit it to cover the entire treatment zone in apattern illustrated in FIGS. 8A-8C. The trajectory is also designed toensure constant equal trace spacing, meaning the spacing between thelines of the trajectory is substantially uniform throughout the region.

FIGS. 8A-8C illustrate an exemplary pattern of HIFU Therapy applicationduring HIFU Treatment with the laparoscopic probe. FIG. 8A isrepresentative of the treatment path 175 soon after the start of thetreatment. FIG. 8B is representative of the treatment path 175 midway,and FIG. 8C is representative of the treatment path 175 near the end.The tracings depict the linear (vertical) and the sector (angular)positions of the transducer 100 during the treatment. This user feedbackis continuously updated during the treatment. Once the treatment starts,the transducer is continuously moving at constant speed and continuouslyapplying HIFU to the tissue treatment area.

FIG. 9 illustrates an image update taken with the imaging transducerduring treatment. The upper panels show the tissue before application ofHIFU Treatment. The lower panels display the images acquired during theHIFU Treatment. Treatment progress may be gauged by the tracing inposition 300 the lower left corner, by the time remaining 302 along theright side of the screen, and by the HIFU-induced echogenic tissuechanges visible in the “after” image 303.

The screenshot shown in FIG. 9 was taken about half way through a HIFUTreatment. In the bottom left HIFU run time indicates that thisparticular treatment has lasted 1 minute and 55 seconds and the timeremaining 302 (on the right side) shows 57 seconds. Once the HIFUTreatment is complete, the water reservoir 200 and associated tubingalong with any components of the kits (including the removable probe tip111) that were used are discarded.

The treatment algorithms of the present invention are designed tosubstantially fill a treatment zone or region selected by the physician.Often, these treatment zones or regions are not symmetrically shaped.Software of the present invention controls a controller 93 to move thetransducer 100 back and forth in the direction of double headed arrow106 in FIG. 1 and to rotate the transducer about its axis 107 asillustrated by arrow 108 in FIG. 1 to provide a continuous treatmentpath within the selected treatment region. As illustrated in FIGS. 8A,8B and 8C, the transducer moves at constant speed, (about 1-2 mm/sec.)to provide spacing between the treatment path followed by the transducerof about 1.5-2.0 mm. The algorithm is designed to keep the spacingbetween adjacent portions of treatment path 175 substantially constantas illustrated at 176 in FIG. 8A and to cross or intersect a previousportion of the treatment path 175 at an angle as close to 90 degrees aspossible (see, for example, intersections 177 in FIGS. 8B and 8C) toavoid retracing the path 175. This pattern of path spacing atessentially 90 degree crossing provides a more uniform heat distributionwith respect to depth inside the treatment region. When path 175 hits aboundary edge of a treatment zone defined by a physician, the path 175changes directions at an angle of about 90°. In FIGS. 8A-8C, thephysician defined a square treatment zone best shown by the filled zonein FIG. 8C. It is understood, however, that the treatment regions may bedefined in any desired shape (typically rectangular) and are often notsquare.

In the illustrated HIFU Therapy, the trajectory stays within boundsparallel to the trajectory path. The bounds limit is a floating-pointvalue specified in millimeters and placed in a property file. Default is1.5 millimeters, checked every 200 milliseconds, but not checked within200 milliseconds of an image update, end of move, or corrective actionsweeps. Upon receiving a 2^(nd) sequential out-of-bounds reading, the RFpower is turned off and the probe is commanded to perform a linear andsector sweep. A level 1 corrective action taken flag will be set andtherapy resumed. Upon reaching the end of the current move, thecorrective action flag will be reset. If two consecutive out-of-boundsreadings are again detected before the end of the move, the probe ishomed, a level 2 corrective action flag is set, and therapy willcontinue. If two consecutive out-of-bounds readings are again detectedbefore the move is completed, therapy is stopped. This “intelligent”checking is incorporated to reduce treatment interruptions due to singleerrors, allows for graceful degradation and minimizes physicianinteraction with the mechanical aspects of the probe. If the probe, evenafter recovery efforts, still fails, this provides an indication oftissue blocking the transducer, or a mechanical problem.

During a single move, a check is made to make sure the distance to thedestination is decreasing. The required decrease value is afloating-point value is specified in millimeters and placed in aproperty file. Default is 0.2 millimeters, checked every 400milliseconds. Not checked within 200 milliseconds of an image update.Corrective action similar to paragraph [0050] will be taken in the eventof errors.

After an individual move starts, the controller 93 makes sure itfinishes within the move time specified in the trajectory list +/−25%and +/−500 milliseconds. Tolerance values are placed in a property file.The controller 93 tracks the move number and makes sure the move numberincrements properly. Checked every 200 milliseconds. Corrective actionsimilar to paragraph [0050] will be taken in the event of errors.

A data validation check is performed at the start of therapy, after eachimage update, and after a pause therapy. The controller 93 makes surethat no move exceeds the maximum theoretical move time and no linear andsector data points are outside the therapy treatment area. If an erroris found the controller 93 reconstructs the data structure and checksagain. In the event of error, the trajectory data is assumed corruptedand therapy is stopped. The controller 93 makes sure that resume datapoints are within 1.5 millimeters of the therapy bounds, value placed ina property file.

A watchdog timer is reprogrammed to cut off RF output if it is notkicked at a 1 Hz rate. If the emergency stop button located on theSonablate® 500 console is pressed, the controller 93 pauses therapy anddisplay the emergency stop icon. The pump 208 is also stopped.

If the probe temperature goes into the yellow zone, the controllerflashes the temperature icon and turns pump 208 on. The controller 93stops therapy if in the red zone upon second sequential reading. Theprobe temperature is read once every 5 seconds. Illustratively, theyellow zone temperature ranges from 25 to 30° C. The red zonetemperature is above 30° C.

If the reverse watts percent is greater than the maximum reverse wattspercent, the controller 93 stops therapy on a second sequential reading.Read once a second. Absolute value watt limits will also be checked toavoid false alarms at low power (10-15 watts). No test within 500milliseconds of an RF on/off transition or power output change.

If the RF power exceeds the probe maximum for two consecutive readings,the controller 93 stops therapy. Median power readings are used based onreadings checked once per second. No test within 500 milliseconds of anRF on/off transition or power output change.

The controller 93 monitors the watchdog timer output to make sure it isfollowing RF output commands. If detected, the controller 93 runs thecode to put the watchdog timer back in the verification mode. Resumetherapy. If additional errors detected, stop therapy.

Paragraphs [0050] to [0058] give an illustration of the built-in safetychecks and error recovery algorithms designed mainly to turn the HIFUdelivery OFF in the case of a failure, or to gracefully recover from amotor/transducer positions error due to probe tolerances, probe/tissueinteractions, or probe failure.

The efficacy, performance, utility, and practicality of these newlydeveloped Sonablate® Laparoscopic (SBL) probes and treatmentmethodologies was evaluated in-vivo using a pig model. Pre-selectedkidney volumes (1 cm³ to 18 cm³) were targeted for ablation (includingthe upper and lower poles, and regions adjacent to the collective systemand ureter), and treated laparoscopically with HIFU in a sterileenvironment using the SBL probes. Integrated ultrasound image guidancewas used for probe positioning, treatment planning, and treatmentmonitoring. The kidneys were removed either 4 or 14 days post-HIFU, andthe resulting lesions were compared to the treatment plan. Resultsindicate that HIFU can be used laparoscopically to ablate kidney tissueat a rate of approximately 1 to 2 cm³/minute, even in highly perfusedorgans like the kidney. Results also indicate that treatmentmethodologies vary depending on the target location, intervening tissue,probe location, and port location.

The following provides an illustrative example of the treatment pathgeneration software used to determine the transducer path based on atreatment plan/region arbitrarily selected by the physician:

  % trajectory12 % rs v1.2 10/6/2004 clear close all % Notes: % Resultscontained in the variable “points”, correctly ordered, in [mm,mm].linsta=0;   %mm (0 to 25) linsto=10;    %mm (25 to 50) secsta=−5;   %deg (−45 to 3) (minimum 6 degree extent...) secsto=5;    %deg (3 to45) fl=35;  %mm; focal length sp=2;  %mm; spacing of traces; put inproperty file gspeed=1.5;     %mm/s; global speed; put in property filewstandoff=15;      %mm; water standoff; determine from “rectal walldistance measurement” plt1=1; %plot plt2=1; %plot lmax=linsto−insta;   %mm; maximum linear travel V1=1.5;   %mm/s; initial guess linearamax=(secsto−secsta)/360*(2*pi*fl);     %mm; maximum sector travel atspecified focal length Va=1.5;   %mm/s; initial guess angle fe=12;  %mm;focal extent disp(‘ ’); disp([‘Linear travel: ‘ num2str(lmax) ’ mm.’]);disp([‘Angular travel: ‘ num2str(amax) ’ mm.’]); vincr=0.01; % velocitychange T=100; t=linspace(0,T,1000); %s tincr=0.02; sperror=0.1; d=1000;wc=0; while abs(d−sp)>sperror,   x=rem(Va*t,2*amax);  y=rem(Vl*t,2*lmax);   for i=1:length(t),     if x(i)>amax,x(i)=2*amax−x(i); end     if y(i)>lmax, y(i)=2*lmax−y(i); end   end %determine 1st slope... m1=(y(2)−y(1))/(x(2)−x(1)); c1=0; % now find thenext sets of points at which the slope is the same as m1... m2=0;count=3; while y(count) > y(2),   count=count+1; end count=count+1; %m2=(y(count+1)−y(count))/(x(count+1)−x(count)); m2=m1;c2=y(count+1)−m2*x(count+1); x2=x(count); y2=y(count); % now find thespacing between these two lines... mp=−1/m1; xd=c2/(mp−m2); yd=mp*xd;d=sqrt(xd{circumflex over ( )}2+yd{circumflex over ( )}2); % showresults for current iteration... if plt1==1,  figure(1);  clf; plot(x,y,‘.’);  hold on;  line([0 amax],[0 0],‘Color’,[1 00],‘LineWidth’,2);  line([0 amax],[lmax lmax],‘Color’,[1 00],‘LineWidth’,2);  line([0 0],[0 lmax],‘Color’,[1 0 0],‘LineWidth’,2); line([amax amax], [0 lmax],‘Color’,[1 0 0],‘LineWidth’,2);  axis(−20amax+20 −20 lmax+20]);  axis equal  line([0 xd],[0 yd],‘Color’,[0 10],‘LineWidth’,2);  plot(xd,yd,‘go’);  plot(x2,y2,‘mo’);  drawnow; endVa=Va+vincr;   wc=wc+1; end Va=Va−vincr; % Now we know the parametersthat will generate parallel lines Vl and Va... % disp([wc sp d Vl Va]);% Find the points in the correct order...   tp=[0 tincr tincr*2];  count=2;   points=[0 0];   done=0;   while done==0,,   xp=rem(Va*tp,2*amax);    yp=rem(V1*tp,2*lmax);    for i=1:3,     ifxp(i)>amax, xp(i)=2*amax−xp(i);end     if yp(i)>lmax,yp(i)=2*lmax−yp(i);end    end    m1x=xp(2)-xp(1);    m2x=xp(3)-xp(2);   m1y=yp(2)-yp(1);    m2y=yp(3)-yp(2);    if sign(ml x) ~=sign(m2x),    points(count, 1:2)=[xp(2) yp(2)];     count=count+1;    end    ifsign(m1y) ~=sign(m2y),     points(count, 1:2)=[xp(2) yp(2)];    count=count+1;    end    tp=tp+tincr;    % check to see when we aredone, be checking if the last point is close to any of the previouspoints...    mindelta=1000;    for i=1:count−2,    delta=sqrt((points(count−1,1)-points(i,1))+2+(points(count−1,2)−points(i,2))+2);    if delta<mindelta, mindelta=delta; end    end    ifmindelta<(sp−sperror), done=1; end   end % shift points...points(:,1)=points(:,1)+(secsta/360*2*pi*fl);points(:,2)=points(:,2)+linsta; if plt2==1,  figure(2);  clf; plot(points(:,1),points(:,2),‘bo’); hold on plot(points(:,1),points(:,2),‘b’);  plot(points(1,1),points(1,2),‘go’); plot(points(count−1,1),points(count−1,2),‘ro’);  axis([−35 −5 55]); xlabel([‘Angular distance in focal plane [mm]’);  ylabel(‘Lineardistance [mm]’);  axis equal; end % determine the total time and traveldistance... dtot=0; for i=1:count−2, dtot=dtot+sqrt((points(i+1,1)−points(i,1))+2+(points(i+1,2)−points(i,2))+2);end disp(‘’);V(secsto−secsta)/360*pi*((fl+fe/2)+2−wstandoff+2)*lmax/1000;disp([‘Total travel: ‘ num2str(dtot) ’ mm.’]); disp([‘Therapy time: ‘num2str(dtot/gspeed) ’ s (‘ num2str(dtot/gspeed/60) ’ min).’]);disp([‘Volume treated: ‘ num2str(V) ’ cm{circumflex over ( )}3(‘num2str(V/(dtot/gspeed/60)) ’ cm{circumflex over ( )}3/min), with a ‘num2str(wstandoff) ’ mm water standoff.’]); disp([‘Focal length: ‘num2str(fl) ’ mm.’]); disp([‘Line segments: ’ num2str(count−2)]);disp([‘Line spacing: ‘ num2str(sp) ’ mm.’]); disp([‘Linear speed: ‘num2str(gspeed) ’ mm/s.’]); disp(‘’);

It is understood that the above example is illustrative only and thatother control software may be used in accordance with the presentinvention.

Although the invention has been described in detail with reference tocertain illustrated embodiments, variations and modifications existwithin the spirit and scope of the invention as described and defined inthe following claims.

1-9. (canceled)
 10. A method of providing high intensity focusedultrasound therapy to a treatment zone comprising: positioning atransducer in relation to a target tissue region of a patient, whereinthe transducer is configured to provide HIFU therapy; energizing thetransducer to provide HIFU therapy at a focal point within a treatmentzone; operating a computer to calculate a path of movement of thetransducer; further operating the computer to move the transducer alongthe path; and energizing the transducer to provide HIFU therapy into thetreatment zone while the transducer is moving along the path, therebytreating contiguous portions of tissue with HIFU.
 11. The method ofclaim 10, further comprising inputting into the computer informationidentifying the location of the target tissue region inside the patient,the computer utilizing the information to calculate the path.
 12. Themethod of claim 11, further comprising the steps of: operating thetransducer in an imaging mode; acquiring an image of the target tissueregion of the patient; at least in part from the results of the image,determining that the tissue in the treatment zone should be treated; andfine tuning the position of the transducer relative to the target tissueregion by software controls.
 13. The method of claim 12, wherein theimage is provided on a display.
 14. The method of claim 11, wherein theinputting of the information identifying the location of the targettissue region includes positioning and resizing a treatment zone tocover the target tissue region.
 15. The method of claim 10, wherein thepath of movement of the transducer covers the entire treatment zone. 16.The method of claim 15, wherein the path of movement of the transducerhas a trajectory which has equal trace spacing and is substantiallyuniform throughout the treatment zone.
 17. The method of claim 15,wherein the transducer is continuously moving at a constant speed andcontinuously applying HIFU to the treatment zone.
 18. The method ofclaim 10, wherein the computer provides a user with feedback during thetreatment and the feedback is provided on a display.
 19. The method ofclaim 10, wherein the computer changes the path of the transducer at anangle of about 90 degrees if the path hits a boundary edge of thetreatment zone defined by a user.
 20. The method of claim 10, whereinthe transducer ceases to apply HIFU to the treatment zone upon theoccurrence of two consecutive out-of-bounds readings prior to completionof the transducer's movement along the path prior to the completion of amove.
 21. The method of claim 10, wherein the computer implements“intelligent” checking to reduce treatment interruptions due to singleerrors.
 22. The method of claim 10, wherein the computer performs acheck to verify that the distance to a destination of the transducer isdecreasing.
 23. The method of claim 10, wherein the computer performssafety checks and recovery algorithms.
 24. The method of claim 12,further comprising the step of providing to a user an image update ofthe target tissue region during treatment.
 25. An apparatus forproviding high intensity focused ultrasound therapy to a treatment zonecomprising: a transducer which is positionable relative to the targettissue region of a patient, wherein the transducer is configured toprovide HIFU therapy; a servomechanism connected to the transducerconfigured to move the transducer along a path in a treatment zone; acomputer connected to the servomechanism and configured to determine thepath and controlling the servomechanism to move the transducer along thepath, the computer configured to have the transducer continuously applyHIFU therapy into the treatment zone while the transducer is movingalong at least a portion of the path.
 26. The apparatus of claim 15,further comprising at least one input peripheral connected to thecomputer for enabling a user to input into the computer informationidentifying the location of the target tissue region inside the patient,the computer utilizing the information to calculate the path.
 27. Theapparatus of claim 16, wherein the input peripheral includes atouch-sensitive display screen.
 28. The apparatus of claim 17, furthercomprising a transducer having an imaging mode, the computer configuredto operate the transducer in the imaging mode and capable of acquiringan image of the target tissue region of the patient, and a display fordisplaying the images.